Aeroplane



Feb- 8 L. MARSCHALL AEROPLANE Filed Jun 25, 1926 'INVENTOR Ludwigfliarschall ATTORNEYS Feb. 8, 1927.

I MARSCHALL AEROPLANE Filed June 25. 1926 3Sheets-Sheet2 WITNESSES L INVENTQR 0 I M A a ATTORNEYS stood at the outset that the safety device may be attached with equal facility to a biplane or other types of heavier than air craft.

The body of the plane'is indicated at10, the usual vertical tail rudder at 11, horizonl tal rudder at 12, and movable flaps of the horizontal rudder at 13. Immediately behind the cockpit 14. of the plane there is a depression 15 in the top of the body between the-wings '16. Thisdepression is located just behinda rail 17 in the body, and when the safety rudder is in its. normal position, it will be screened from the action of the 'windby the rail 17, whereby no, additional air resistance is offered by the-safety wing. ..'lhe construction of the safety wing itself 7 may be best seen from Figs. 8 to 10 inclusive,

in. which, it will be notedthat the wing includes a swinging frame consisting of a pair of arms 19 connected at one end by a cross shaft 20 which serves as a pivot for the frame. Shaft 20 is journalled in suitable bearings in the top of the aeroplane body and isactedupon by coiled torsional springs 21'to retain the frame 19 in the horizontal position illustrated in Fig. 8. A generally rectangular frame 22 is pivoted near one end between the free ends of the arms 19, this pivot point being indicated by the reference numeral 23. :The larger portion of the frame 22 extendsrearwardly from the pivots 23 in Fig. 8 and the smaller portion thereof extends forwardly from the pivots. A cross shaft} 24 carried by the forward end of the frame 22 serves as'a pivotal mounting for a flap; 25, upward swinging movement of which is limited by fingers 26 projecting inwardly from the frame 22. The flange 26 which overlies the forward end .of the frame plane dives at a dangerous angle,the latch 27 will overcome the spring 28 and. willswing forwardly, releasing the flap. and the forward end of the frame 22. Frame 22 is covered'with canvasor other suitable material 30to form the safety rudder proper, and the flap is designed to initiate up- 7 ward swinging movement of the safety rudder to the vertical position shown in Fig. 5; V y In order to initlate upward movement of the flap after the gravity latch has been released, I provide a pair of cylinders which mayeither be mounted in the body of the aeroplane or secured to the frame 22. Operating pistons 31 connected "to the flap 25 near its hinged edge are adapted to be Thus, as the plane dives forwardly, the gravity latch swings out of operative position, and the balls 32 rolling in the, cylinders will kick the flap to' the position shown in F 10 and in dotted lines in Fig. 8. As the flap is raised, the wind has a chance to get under it, and pick theentire swinging frame 19 up bodily, swinging this frame with its associated rudder 30 to the vertical position of'Fig. 5, where it is stopped by any suitable means, such for instance as the stop brackets 33 secured to the body. I

As the safety rudder swings'to the vertical position of Fig. 5, it will offer enough air resistance to restore the plane to horizontal position andin this, restoration will be assisted by the tail rudder 18 in a manner to be later described. I When the safety rudder swings to the vertical position of Fig. 5, it will be noted that the portion thereof below the hinge 23 offers considerably more area to the wind than does the portion above this hinge.

Swinging movement of the frame 22 on the hinge 23 is prevented however, by the presence of a crossbar 35 carried by the lower ends of arms 36 which in turn are pivotally connected at 37 'to arms 38 PlVGtQCl at 39 to the frame bars-19. Extensions of. the arms 38 are counter-.weighted at 40 and the lower ends of thearms36 are provided with eyes or similar devices 41 which afford a sliding connection on the lower or. rear ends of the frames 19. p The counter-weighted arms are so arranged-thatwhen the safety rudder is in the position of-Fig. 8, the arms will holdv the cross bar 35 in position to prevent rearward swinging movement of the rudder 30. When the rudder is in the vertical position of Fig. ohowever, and the plane gradually rights itself and is restored to horizontal position, thecounter-weights 40 will cause -thearms 38 to swing rearwardly to the position of 9, therebyslidingthe cross arm 35 downwardly, so that it will clear the lower end of the rudder 80. Atthis time, differential air pressures on the rudder will swing the latter to the horizontal position 1 of Fig. 6, and the rudder will cease to function. Inasmuch asthe rudder offers no appreciable air resistance'in the position of 6, the frame 19 and its-associated mechanism will immediately be restored to its normal inoperative horizontal position by the springs; 21. i

As the rudder swings back to the position of Fig. 8, it will automatically latch itself by the gravity. latches 27, acting on the cam surfaces 45 of these latches to force the coiled expansion'springs 46 as soon asthe 'ically rendered inoperative by associated univers l;

safety rudder reaches the yertical position above its tail.

- tion bythe connter-weightsslO as'the frame rudder 13, swinging the latter downwardly into ,the gliding position illustrated in Fig.

cf ig- 55 an that the la h g ba 5 automatically restored to inoperative posil;9, 1: an its ssoci t d ru der e to d t horizontal position. In Fig. 6 I have indicated the ru der 3 i t leas d y it a ching bar and swung to horizontal position.

Immediately after it reaches this position, it

will be restored to the inoperative position of Fig. 8 andFig. 1. At the same time the rudder 3O swings to the position of f Flg'.

6 it acts to automatically control the tail 6. Thus, as the nose of the plane is swung sharply upwardly by the combined action of the safety rudderfand tail rudder in Fig. 5, the position of the tail u der w l. b

versed in time to prevent the plane from making a complete loop and from swinging its nose too far, upwardly.

The action of the springs 21 which restore the frame ,19 audits associated rudder to inoperative position may beaided if necessaryor desirable by the action'of counterweightsQ secured tothe'shaft 30. .These counter-weights are desirable because they offer. oneconvenient attachment for the operating connections between the frame 1Q and the tail rudder which will be, later described.

Pivotally connected to the cross shaft is a flap 4.9 normally overlying the main body portion of the rudder 30. This flap ,becomes active in the event that the-plane back-slips, asshown in Fig. 1 The flap is operatively connected to a pair of counter-weights which serve to initiate movement ,of the flap when the plane reaches a dangerous angle with its nose too high Thus, if we assume that the frame 19 and all of its. associated mechanism is in the normal position of F ig. 8,

and the plane starts to baclrslipj, the counter weights .50 will become operative as soon. as the plane reaches a dangerous angle, serving to slightly lift the 'fr'eeedge of the-' flap 4'9 and permitting the wind to. get

under the flap and raise it to the position of Fig. 7. As the flap reaches the position 1 of Fig. 7 further. movement thereof is limited by the fingers 2.61 and the flap will actto restore the plane to horizontal position, as will be readily understood. When the plane again goes forwardly, the wind pressure on the forward face :of the flap 4L9 -will automatically swing it' back to inop-' .erative position. I I

' I have thus far described the action of the safety rudder on a nose dive, and the action of the flap 49 on'a back slip. I shall now explain the manner in which movement of the safety rudder isautomatically corelated with the movement of the tail rudder, so that the tail rudder assists the safetysrudder from a nose div t ho o al.po i ion, P vent th p ane from, m k ng a l ap after it has been reset to either climbing or; no ma flying Fa -1 5 1- aft t e af y rudder has performed; its function and been :r'estored'to normal position.

he a lfr d r e ntrol me h m m may be best seen from Figs. 2, 3 and 1, and is adap ed oact 0 1 t e main .60 of. the plane. I

his c nt o le er s pi oted at 6:1 nd

the controlling cables 62, (5,3 for the rudder 13 are connected to the lever .60 above and below the pivot respectively. Therear ends of these ables connect withc a l; ar -5t, 6. rig d with-th ru d r it so t at ferward movement of thelever 60, will-tend to ole control lever Vate' the rudder, causingthe plane to climb,

a d r arwa dmovem n i lten lto lower the same, ca i g he p a e to glide: W t

A pair of automatic control aleflvers'lifi,

control mechanismi OlQ'p this 67 arecrossed and pivoted on the shaft 61,

the upper ends of theselevers being adapted to engage one side or the other of the control lever '60, in theevent that 'the levers .66 or .67 are. locked on their pivots.

A spring .68 connects thelower ends of the levers 66, 67 and tends to draw theseends toward each other. The levers are normally held apart against the action of the spring by a pair of. latches 69.connectedto cables which run" over suitable pulleys '71 and are connected to parto'f the frame 19. As

illustrated, these latches a-refdirectly connected'to an eye 72011 .the arm which carries the counter-weight 18. "Thus, as the frame, 19 mfovesupwardly from the full line toward thedotted' line position .of- Fig. 1 cable 70 will be pulled to disengage the latches .69 and permit spring 68 to act upon the levers 67 and 66, drawing them together.

Thepivot shaft 61 of the levers 60, 66

and 67 is preferably mounted between a pair of'upstanding brackets I A disc 74s .eccentrically mountedfon one of the brackets '73 is rotatable about its eccentric pivot Y75, and is acted upon by a coiled spring. .71 anchored to the bracket 7 3. Disc Ttis connected to the lever 67 by a belt or other suitable connection 77, so that as the disc is swung from the full line to the dotted line position of Fig. -43, it will carry with it the lever The disc is ordinarily held in the position of Fig; 1 against the'action of its spring a-latch 78 pivotedto the 'lll) 1 into disenga l/Vhen the latches 69 bracket 73,-this latch being spring pressed ing position by a coiled exlever forwardly and consequently has lifted the tail rudder 1.3. In Fig. 4, I haveshown the position of-- the parts aft-er latch 78 has been released; and permittedthe spring 76 to shift the disc 74 to its opposite extreme position- In this position it will be noted that the levers 66 and 67 are drawn J1 inwardly by the. spring78. against the disc '74'and that' theupper-end of the lever 67 has moved the control lever rearwardly, swinging the tailrudder downwardly and throwing the plane into gliding position.

pulleys 81 to the frame 22.

To effect disengagement'of the latch 78 from the disc7 4, I connect this latch through the interinediacy of a cable 80 run over Thus, when the frame swings from the vertical dotted line position indicated in Fig. 1 to the horizontal dotted line position, cable 80 will be pulled to retract the latch 78 and permit the disc 74 to be shifted to the dotted line position I a cable .86 anchored to one end of a bell.

. of Fig. 4.

Means is also provided for automatically restoring the lever 60 to its central or neutral position even though the levers 66 and 67 are unlatched, and without requiring manual operation of the lever 60. To accomplish this result, I connect lever 66by a slot and pin connection 82' to an arm v83 drawn rearwardly by a coiled contractile spring 84.

Rearward shifting movement of the arm 83 under the influence of spring 84 is normally prevented by a spring latch 85 which ensages the arm. This latch is connected to crank lever 87 disposed in the path of movement of the counter-weight'48. The spring 84 is stronger than the spring 71, so that if we assume the latches 69 to bedisengaged, and the disc 74 swung to the full line position of Fig. 3 by the action of its spring,

release of the latch 85 will permit the spring 84.to balance or counteract the spring 71, and consequently shift levers 66 and 67 to bring the levers 60 to their neutral central position. 7

Having thus described the general. construction of the automatic control lever system, I may briefly outline its operation in connection with the movements of the safety rudder.

Assume that the parts are in the full line position of Fig. l, with both levers 66 and plane looping the loop.

67 latched, with the latch 78 engaging the disc 74 and with the latch 85 out of engagement with thearm '83, As the supple- 7 mental safety wing swings to, toward the vertical positionshown in Fig. 5, the counter-weight 48 will first move off of the bell crank 87 and permit the latch 85 to operate andengage the arm 83. Upon further 'movement of the safety rudder to vertical position, the arm of the counter-we1ght48 will have taken up the. slack incables and W111 retract the latches. Levers 66 and 67 will spring to the dotted l-ineposition of Fig.4, shifting the control lever 60 forwardly and swinging the wing 13 upto climblng posltlon. 'At' th s time the parts are in the position shown in Fig. 5,, with both the safety rudder and the tail rudder tending to restore the plane to normal position; 7

As soon as the plane has'been righted sufiiciently to permit the counter-weights 40 to act, and release the rudder 80, this rudder willswing to horizontal position, and as it does so, will pull upon the cable 80.to

retract'the latch 78. It is to be borne in H 'mind, that at this time the arm 83 is still latched, and unlatching the disc 74 will simply permit the spring 71 to. act and shift the'disc' 74'to the dotted line position of Fig. 4, which is the full line position of Fig. 3. l/Vhen this occurs, the relative positions of the levers 66 and 67 will again be shifted to an extent determined by the position of the disc 74, and the control X lever 60 will be pulled rearwardly, throwing the tail rudder 18 downwardly into gliding position. rangement, any tendency of the nose of the plane to continue swinging up after horizontal position is reached, is successfully V counteracted, and there is no danger of the in the full line position of Fig. 3, the relative positionof the tail rudder and safety rudder is shown in Fig. "6. In this figure, it will be. noted that the tail rudder 13 is swung downwardly to gliding position and. the safety rudder 30 is in horizontal position ready to be returned to inoperative position by its'springs and counter-weights 21- and 48 respectively.

WVhen the parts have reached the position'of Fig. 6, the next movement. of the safety rudder will be back toward the inoperativepo'sition of Fig. 1. As the safety wing swings to inoperative position, the

counterweight 48 kicks the bell crank 87,

releasing the latch and permitting the spring 84 to vact against the springi76j At this time, allof the latches will be inoperative, and the position of. the disc will be predetermined by the relative strengths of the springs 84 and 76; Preferably, .the combined action of these springs will be to shift With the levers Byvirtue of this ar- 7 ing or slight gliding ofthe plane."

the discs to the positionindicated in dotted llnes in Fig; 3, with" consequent movement'of" the control lever to normal position. ,Ob-

viously, this last movement of the levers could be used to cause either a slight climb- To recapitulate,the three automatlc movements of the safety rudder are accompanied by three automatic movements of the tail rudder.

' the vertical position ofFig; 5, the tail rudder "slightglidingf or climbing angle, as may be swings upwardly to the climbing position of Fig; 5; As the safety rudder svvings to the horizontal positionof Fig. 6, th e tail rudder swings to the-'glidingposition of Fig. 6, and

asthe safety ILlClClGIISWlIlgS to the ifnopera tivefpositlon of Fig; 1 ,ithe tail rudder swings to its normal neutral position, or'to either a desired, and'as may he predetermined by therelative 761'. in; extremely simple form of mechanism has been sliovvn for' aut'omatically' resetting thelevers. 66, 67 ,and their associatedmechanism; The resettin'gkdevice is in the nature ofza lever, 90.to which is pivoted a short linke91,connected'bytoggle levers 92, 93 to the upper end of lever 66 and the lower end of lever '67 respectively. As theresetting lever is moved rearvv ardly, the lower ends of the leversf66 and" 67 Will be separated until they engage their latches 69; The disc 74f v'v'illlb'e carried with the lower'end of the '1ever1j77 funtil 'is engaged by its latch 78. The arm 83' will be carriedby V lever '66 to a position 'Where'it may be en gaged-by the latch 76, as soon as the counter weight 48, moves off the bell crank.

might be resortedto for controlling the tail lever from the safety Wing ,;and' for restoring thesafety ,wlng to inoperative position after i it has served the purpose. [In connection with the restoration ,of' the ,saf'ety'wving,

"also contemplate the use of a vacuum tank in the event that. the torsional springs and countereight prove too heavy or too cumbersome. 4 y f, f

9 Various changes, and alt'erationsmightbe made in the fgeneral'form and arrangement I descrihed-j tvithout departing; fromv the invention; 1 HenceFI do not Wish to limit mysel'flto ,tliez' details set forth-,butf shall :eonsider. myself ,at liberty to make such changes and" alterations as fairly fall within:

t isn it and Scope of the appended claims. ,HI claim:

' Aniaeroplane including a-frame pivot- As the safety rudder swings to strengths of the sprin '84 and.

ed to thezbody of theplane and normally held" in inoperativeposition against" said" body; a safety rudder pivotedintermediate its ends intheframe, means forpreventing pivotal movement of the rudder in" the frame" as the rudder'andiframe'svving upwardly and 1 rearwardly 0n the frame pivot.

2. An aeroplaneincluding a frame pivoted to the body ofthe plane and normally held in inoperative positionagainst said body, a' safety rudder pivoted intermediate its ends in the frame; means for'preventing pivotal' movement of the rudder in the frame as the rudder and? frame Swing upwardly and rearwardly' on the' frame pivot, I and means" for a rendering said preventing meansinop} erat ve when the rudder and frame'reach vertical position. 1 I I 3. An aeroplaneincluding a frame'pivote'd tothe body of the plane and normallyheld' in inoperative position. against said body,.

safety rudder pivotedintermediate its endsf.

in the frame, means for preventing pivotal movement of therudde'r' in the' fra-me'i'as the rudder and frame swing upwardlv' andre'ar Wardly on the frame plvot, sa d means 1n-- cl'uding'a cross'barbloclting swingingmove men't ofthe rudder; v a v An aeroplaneincluding a frant le piv oted tothe body of the planeand-normally held" in inoperative position against said? body, a safety rudder pivoted-i intermediate 1 its ends inthe frame, means forpreventing pivotal'movement oft-he rudderin the frame as the rudder and frame swing upwardly and" rearwardly" on the framefpivot, said? means including a cross bar blocking swing ing movement of thejrudder, and gravitation'ally operable eans "for shifting? the cross bar out 'of bloclring; position when. the frame and rudder reach vertieal'position 5;.i An aeroplane including a frame pivf oted tothe bodalof the:pl'anef and normally' held in, inoperative position" ztgeiiiistiLsaid; body, asafety rudder pivoted intermediate pivotal movement of the rudderi'ri the frame as the rudder and frame svvingjfupwardly means including acrossbarbloeking swingmg movement of the rudder, and 'gravita tionally operable means for' -sh1ft1.ng the its endsin the frame, means;forfpreventing' 1 cross bar out of blocking position when} the frame and rudderireach' verticaljposition,in-

cluding arms slidably oonnectedt'o the frame and carrying; the cross ban and counte'r eighted} arms Ipivotally connectedi to the a frame and to saidifirst mentioned-arm's;

G'LAn aeroplane including a frame pivotedflto the body ottheplanei and normally held in inoperativeposition 'ia'gainist' said body, a safety rudde pivotediintermediate itsendsfin the fjr ame -means forjpreventing v a V pivotal movemento f their-udder in the "frame as the -udder" and frame swing upwardly and rearwardly on the frame pivot, and means for rendering said preventmgmeans inoperative when the ruddera-nd frame reach vertical position, said rudder being pivoted near its upper end, whereby when it IS released differential air pressures 'on its two ends will swing it to approximately horizontal position.-

7 A device of the class set forth in claim 1, wherein gravity latches normally retain i the rudder against upward swinging move- 7 ment. Y

8. A'device as set forth 'in' claim 1, and whereinthe rudder and its associated mechanism-are normally disposed in a depression in. the top of the body of the'plane whereby they offer no air resistance when in inoperative position.

9. An aeroplane including a frame piv- Y for rendering said preventing means inop-e oted to the body of the plane and normally 1 held in inoperative position against said body, a safety rudder pivoted intermediate its ends in the frame, meansfor preventing pivotalmovementof the rudder in the frame 'asFtherudder and frame swing upwardly and rearwardly on the frame pivot, means erativewhen the rudder and frame reach vertical position, said rudder being pivoted near its upper end, whereby when it isreleased difierential air pressures on its two ends will swing it; to approximately'horizontal position, and means acting on the frame to restore the latter to inoperative position when the rudder has swung to approx-' imately horizontal, position under the pres- V 'sureofthe air against it. i

10.' An? aeroplane including a frame pivoted to the body of the plane and normally held in;v inoperative position against said body, a safety rudder pivoted intermediate itsends in the frame,means for preventing Y pivotal movementof the rudder in the frame as the rudder and, frame swing upwardly and rearwardlylon the frame pivot, and

means for initiatingupward swinging movement of the rudder and'frame as the aeroplane dives at a dangerous angle. a

, 11." An aeroplane including a frame pivoted. to thebody of theplane and normally held in inoperative position against said body, a safety rudder pivoted intermediate its ends inthe frame,,means for preventing pivotal movement of, the rudder in the frame 7 as, the rudder and frame swing upwardly and rearwardlyon the fran7ie pi-vot, and

' means for initiating upward swinging movement of the rudder and frame, as the aero[ 7 plane dives, at a dangerous anglas id means including ai-flap secured to'the rudder ant automatldmeans liftlngfthe flap; r

. 1 12. An aeroplane including a framepiv-V V otedto thebodyofthe planefand normally 'held' in inoperative position against, said I body, a safety rudder pivoted intermediate its ends in the frame QmeaiiS for preventing a pivotal movement of the rudder in the frame as'the rudder and frame swing upwardly and rearwardly on the frame pivot, and,

means for initiating upward swinging movement of the rudder and frame as th'e aero-l plane dives at a dangerousanglmsaid means iucludmg flap secured to the rudder and automatic means lifting the flap, including a gravity operated kicker mechanism.

13. A deviceof the class described in claim 1, and wherein a flap hingedly connected to the rudder is adapted to automatically swing to vertical po-sitionwhen the plane backslips. 14. In an aeroplane including a tail rud der formed with a pivoted section, a frame pivoted to the top of the body of the aeroplane,.a safety rudder pivotally mounted,

in the frame and locked against pivot-a1 movement therein, except when the frame" is in approximately vertical position, said frame and the safety rudder being adapted to swing upwardly when'the plane dives at a dangerous angle, and operative connections between the safety rudder-and the pivoted in approximately vertical position,--said" frame and the safety rudder being adapted to sw ng upwardly when the plane dives vat a' dangerous. angle, 7 and operatlve connec tions betweenthe safety rudder and the pivoted section of the tail rudder, to swing r i the tail rudder section to climbingpositionas the safety rudder swings toward vertical position.

-16. ln an' aeroplane including a tailma der formedw'itha pivoted section, a frame pivoted tothe top of the body ofthe aeroplane, a safety rudder pivotally; mounted in the frame and locked against pivotal movement therein, except when the frame is in approximately vertical position, said i frame and thesafety rudder being'adapted to swing upwardly when the plane dives at a dangerous angle, andfoperative connec tions between thesafety rudder and the piv} i ote'd section of the tail rudderto swing the tail rudder section in "climbing position as the safety rudder swings toward vertical posltion, said safety rudder; bem'g' eecentrlcally pivoted inthe frame and automatically released for free pivotalfmovement when the frame reaches vertical'positlon,whereby the safety rudder will' be swung to approxi-l mately horizontal positionby'the action of f r;

the wind.

17. In an pivoted to the top of the body of the aeroaeroplane including a tail r'u dder formed with a pivoted section, a frame plane,a safety rudderpivotally inounted in the frame and locked against pivotal movement therein, except when the frame is in approximately vertical position, said frame and the safety rudder being adapted to swing upwardly when the plane dives at a dangerous angle, and operative connections between the safety rudder and the pivoted section of the tail rudder to swing the tail rudder section in climbing position, as the safety rudder swings toward vertical position, said safety rudder being eccentrically pivoted in the fraine and automatically released for free pivotal movement when the frame reaches verticalposition, whereby the safety rudder will be swung to approX1 for swinging the tail rudder, section to glid ing position as the safety rudder swings to horizontal position. 7

ILUDWIG MARSOHALL- 

